In response to a request from the General Services Administration (GSA), an evaluation was made of possible hazardous working conditions in the Post Office/Courthouse Building (SIC-9311), located in Louisville, Kentucky. Concern was expressed due to the fact that 10 of 28 persons working in Room 648 of the U.S. Internal Revenue Service Audit Division Office for a period of at least 5 years had developed cancer. Of these, nine died and one was considered cured. A major fire in 1960 had damaged ceiling tiles on the sixth floor which reportedly contained asbestos (1332214). Individual air conditioning units were installed in 1960. Due to the fact that the filters in these conditioners were rarely changed, it was suggested that asbestos fibers were lodged in the filters and some were blowing through the system, particularly into room 648. Samples of the ceiling tile were tested; no asbestos was found. A review of the death certificates indicated that of the 13 deaths occurring to employees between 1963 and 1980, four were due to cardiovascular disease, one from bacterial infection, and eight from cancer. The cancer sites included four lung, two colon, and two breast. As there was no evidence of asbestos found, and as there was not deemed to be an unusual occurrence of cancer deaths involving any particular organ, the author concluded that the suspected hazard at this workplace did not exist.